The present invention relates generally to a high density connector assembly and more particularly to improvements in a wirebonded high density connector assembly.
High density connectors are well known in the electronic industry as well as the automotive industry. In both industries the need for complex electrical connections must be married with an ever increasing need for the minimization of the size and weight of all parts. These needs have lead to the development of high density connectors. High density connectors provide a large number of individual electrical connections located within reduced size connector components. Although developments in high density connectors have lead to known improvements in connector density, minimization of their size has been limited by the ability to attach such connectors to the circuit boards to which they provide electrical communication.
Each individual electrical connection within a high density connector must be provided with a unique electrical path to the circuit board. Known methods of providing such pathways, such as solder connections, often create limitations on the layout and size of the high density connector. The electrical pathways created by solder and other conventional methods require surface areas that are known to prevent the individual connections within the high density connector from being placed too close to one another. A method of connection, however, is known that utilizes very thin connections to create pathways between a high density connector and a circuit board. This method is known as wirebonding. The electrical pathways created by wirebonding have small cross-sectional areas and may be placed within close proximity to each other. These characteristics make wirebonding highly suitable for use with high density connectors.
Although the scale of individual wirebonds make them naturally suitable for use with high density connectors, they have additional characteristics that have served to limit their use and have restricted the size and density of high density connectors employing them. The thin arcs of metal created by wirebonding become fragile when the distance between connection points becomes either too great or the arcs cover too great a vertical distance. This characteristic limits the use of wirebonding in applications that may be exposed to vibrations. Applications within industries such as the automotive industry often require their electrical components to survive environments with vibrational characteristics that prevent the use of such long wirebonds.
It is known that to circumvent the vibrational deficiencies of long wirebonds the high density connectors used in such environments may be limited to two rows of pins within the connector. Although this limits the length of the wirebonds, it requires longer connectors to accommodate a given number of electrical connections. Since size and density of such connectors is often a primary characteristic, such solutions are undesirable. High density connectors with three and four rows of connections often require pathways to the circuit boards on both sides of the high density connector. This limits the size and design flexibility of such connectors making such solutions undesirable for many applications.
Another method of compensating for the lack of vibrational resiliency in wirebonds is through the use of complex connector designs. One common connector design uses pin elements within the high density connector. A clear pathway from the ends of these pins to the circuit board must exist to create the wirebond. To accommodate these pathways the geometry and size of the multi-row connectors are restrained. One known method to accommodate such pathways utilizes staggered spacing between rows of connectors. This is undesirable since it requires a greater area for a given number of connections. Another known method places the connection points on surfaces 90 degrees to each other. While this decreases the length of the wirebonds, present designs often increase the vertical distance of the wirebonds and therefore can have undesirable vibrational characteristics.
Therefore, there is a need for a high density connector that can utilize the positive characteristics of wirebonding to create a highly dense connection pattern, while eliminating the poor vibrational characteristics, size limitations, and manufacturing costs associated with known designs.
It is therefore an object of the present invention to provide a high density wirebond connector assembly that improves the connection density. It is a further object of the present invention to provide a high density wirebond connector assembly that reduces the assembly""s sensitivity to vibration, reduces the assembly""s size, and reduces the cost of the assembly""s manufacture.
In accordance with the objects of this invention, a high density wirebond connector assembly is provided. The high density wirebond connector assembly includes a connector housing containing a plurality of pin contacts. Every two rows of pin contacts merge onto one shelf to provide a high density contact surface. The connector housing is comprised of a plug end for electrical communication with an outside source and a shelf end for electrical communication with a circuit board.
The high density wirebond connector assembly further includes a circuit board containing a plurality of laminate layers. A plurality of wirebond pads form signal contacts for each of the pin contacts. The wirebond pads are positioned on at least two of the laminate layers so that the distance between any single wirebond pad and its corresponding pin contact is minimized. By placing groups of wirebond pads on separate layers of laminate, the wirebond pads can be placed in close proximity to each other and may be positioned in close proximity to their corresponding pin contact.
The high density wirebond connector assembly also includes a plurality of wirebonds. The wirebonds connect each individual pin contact with its corresponding wirebond pad and provide electrical communication between these elements.
Other objects and features of the present invention will become apparent when viewed in light of the detailed description of the preferred embodiment when taken in conjunction with the attached drawings and appended claims.